The Research Of Stress And Crack Of The 0 # Blocks Of The Continuous Rigid Frame Bridge

Prestressed concrete continuous rigid-frame bridge is one of the most extensive bridge type used at present. But the problem of crack appears in the construction or service phase at the same time, which should be taken seriously by all of us.Based on the engineering background of Chang Yang major bridge on the main road in Yichang of Hubei tight in Enshi, the theoretical analysis was taken after cracks appeared on the web of the box beam in the construction phase against the 0 # blocks of the bridge.By reading plenty of references home and aboard, the causes and classifications of cracks in concrete structures were introduced in this paper, also the may factors cause cracks were summarized in the paper. At the same time, the basic theory of temperature field,hydration heat of the concrete and shrinkage of concrete were introduced in this paper.Based on the background of the 0 # blocks of Chang Yang major bridge, the position where the cracks developed, the length and width of the cracks were analyzed. The general finite element analysis program ANSYS was used to analyze the 0 # blocks of the major bridge.The factors such as the hydration heat , shrinkage of concrete, temperature differences by the sunlight etc which may cause cracking of the 0 # blocks were analyzed separately.According to the investigation report of the cracks provided by the detection unit, the correctness of the theory analysis was verified. Then the various factors was coMPared and the sensitive factors that caused the cracks of 0 # blocks of Yu Quanxi major bridge was tried to find out.Finally, a reasonable construction scheme was made out to against the cracking of 0 # blocks in order to improve the condition of 0 # blocks under the effect of the hydration heat , shrinkage of concrete, temperature differences by the sunlight etc. Some measures for daily maintenance and structural measures were put forward to against the cracking of 0 # blocks as well.